I loved every OD strains I've had a chance to sample,never smoked primera dama and I'm thinking about buying some (although it seems they can only be bought in feminized form) but I'm a bit suspicious about this one. A pure Mexican from the 60's supposed to be ready by the end of September seems too good to be true. If it is what the breeder claims it to be that would be an amazing breeding tool for growing two seasons tropical girls in a four seasons zone without the introduction of short flowering charas plant.
But I really doubt, even by selecting the earliest phenos, one can get such a result out of a mexican without some crossing at some point. But I'm far from being an expert of mexican landraces so I might be wrong
Time is the element you haven't accounted for, 45-50 years of it. Good breeders w/ decently large plant populations can do a lot with that. The other side of it is that Culiacan, Durango & Zacatecas aren't that far south & that field grow landrace cannabis exhibits considerable variation.